‘Let all bitterness and wrath, and anger and clamour, and railing, be put away from you with all malice, and you be kind one to another, tender-hearted, forgiving each other, even as God also in Christ forgave you.'
Paul now sums up this section by including further things to be avoided, the signs of the old man. ‘the man that they were', and by directing them to reveal the new man, ‘the man that they now are'.
The signs of the old man are bitterness (pikria - bitterness, animosity, harshness, tartness of speech), wrath (thumos - anger, passion, rage, touchiness), anger (orge - indignation, wrath), clamour (krauge - shouting clamour, here arising from passion), railing (blasphemia - evil speaking, blasphemy). All these describe loss of the self-control, which is a fruit of the Spirit.
In contrast the signs of the new man are kindness, consideration for others, tender-heartedness, a forgiving spirit, a positive life of self-giving. And we are to be like this in the light of the fact that God, for Christ's sake, forgave us and because we are now ‘in Him'. As Jesus said with regard to the prayer He taught His disciples, ‘if you do not forgive men their trespasses, neither will your Father forgive you your trespasses' (Matthew 6:15). Those who have been pardoned must not themselves regularly be finding fault.
‘Even as God also in Christ forgave you.' With Paul everything in the end comes back to the cross. There we died with Christ, and there the old man was put to death. It is because we have been given hope that we must give others hope. And God in Christ forgave us so that we must be willing to forgive others. In this we are to be imitators of God (Ephesians 5:1).